Ratio pump and method

Abstract

A ratio pump for delivering first and second liquid beverage components in a desired ratio comprising a motor and a pump driven by the motor. The first beverage component is pressurized and is used as the driving fluid for the motor. The second beverage component is pumped by the pump. The first beverage component is exhausted from the motor and delivered along with a second beverage component delivered by the pump. The motor, which may include a piston, requires a predetermined amount of the first beverage component in order to drive the pump to deliver a known volume of the second beverage component.

We claim: 
     
       1. A ratio pump for providing first and second liquid components in a desired ratio wherein the first liquid component is pressurized, said ratio pump comprising: a motor including means defining a motor chamber, a reciprocable member reciprocable in the motor chamber, an inlet for admitting the first liquid component into the motor chamber to drive the reciprocable member with a predetermined volume of the first liquid component being used to drive the reciprocable member through at least one of its strokes, and exhaust for exhausting the first liquid component from the motor chamber, valve means for controlling the admission and exhaust of the first liquid component into and out of the motor chamber, respectively, and means for controlling the valve means so that the first liquid component can reciprocate the reciprocable member in the motor chamber;   a pump including means defining a pumping chamber, a reciprocable pumping member reciprocable in the pumping chamber, an inlet for admitting the second liquid component into the pumping chamber, an outlet for discharging the second liquid component from the pumping chamber with each delivery stroke of the pumping member pumping a predetermined volume of the second liquid component;   means for drivingly coupling the reciprocable members whereby the motor reciprocates the reciprocable pumping member;   a receiver coupled to the exhaust of the motor to receive the first liquid component exhausted from the motor and the outlet of the pump to receive the second liquid component delivered from the pump whereby the receiver receives the first and second liquid components in the desired ratio; and   said controlling means including bistable spring means for operating the valve means, a movable member for driving the bistable spring means over center in both directions, and first and second pivotally mounted levers at opposite ends of the motor chamber and pivotable by the reciprocable member of the motor as it nears the end of each stroke for moving the movable member whereby the bistable spring means operates the valve means.   
     
     
       2. A ratio pump as defined in claim 1 wherein said coupling means includes means for coaxially coupling the reciprocable members. 
     
     
       3. A ratio pump as defined in claim 1 wherein the reciprocable member of the motor has a working face on which the first liquid component acts and the reciprocable pumping member has a working face which acts against the second liquid component to pump the second liquid component, said working face of the reciprocable member of the motor having a larger area than the working face of the reciprocable member of the pump, said receiver includes first and second conduits leading from the motor exhaust and the pump outlet, respectively, and a common discharge conduit joined to both of the first and second conduits, said second conduit being incapable of shutting off flow of the second liquid component whereby the likelihood of a failure resulting from overpressurizing of the second conduit is reduced. 
     
     
       4. A ratio pump as defined in claim 1 wherein said pump includes a removable seal gland for sealingly cooperating with the reciprocable pumping member and said seal gland and reciprocable pumping member are replaceable to change said desired ratio. 
     
     
       5. A ratio pump for providing first and second liquid components in a desired ratio wherein the first liquid component is pressurized, said ratio pump comprising: a housing;   means defining a motor chamber in said housing, a double-acting piston reciprocable in the motor chamber, an inlet for admitting the first liquid component into the motor chamber to drive the piston with a predetermined volume of the first liquid component being used to drive the piston through at least one of its strokes, an exhaust for exhausting the first liquid component from the motor chamber, valve means for controlling the admission and exhaust of the first liquid component into and out of the motor chamber, respectively, and means for controlling said valve means so that the first liquid component can reciprocate the piston in the motor chamber;   means defining first and second pumping chambers in said housing, first and second reciprocable plungers coupled to the piston and reciprocated thereby in the pumping chambers, respectively, an inlet for admitting the second liquid component into the pumping chambers, an outlet for discharging the second liquid component from the pumping chambers whereby each delivery stroke of the plungers pumps a predetermined volume of the second liquid component;   a receiver coupled to the exhaust of the motor to receive the first liquid component from the motor and the outlet of the pump to receive the second liquid component from the pump whereby the receiver receives the first and second liquid components in the desired ratio; and   said valve controlling means including bistable spring means in said housing for operating the valve means, a movable member on said housing for driving the bistable spring means over center in both directions, and first and second pivotally mounted levers at opposite ends of the motor chamber and pivotable by the piston as it nears the end of each stroke for moving the movable member whereby the bistable spring means operates the valve means.   
     
     
       6. A ratio pump as defined in claim 5 wherein said piston and plungers are coaxial and the pumping chambers are at opposite ends of the motor chamber. 
     
     
       7. A ratio pump as defined in claim 5 wherein said pump includes a removable seal gland for sealingly cooperating with the first plunger and said seal gland and said first plunger are replaceable to change said desired ratio. 
     
     
       8. A reciprocating device comprising: a housing having a chamber therein;   a reciprocable member mounted in said chamber for reciprocating movement therein and having first and second working faces;   an inlet for admitting driving fluid under pressure to said chamber;   an exhaust for exhausting the driving fluid from the chamber;   valve means for controlling the admission and exhaust of the driving fluid into and out of the chamber, respectively;   controlling means for controlling the valve means so that the driving fluid can reciprocate the reciprocable member in the chamber; and   said controlling means including bistable spring means for operating the valve means and driving means for driving the bistable spring means over center in both directions, said driving means including first and second levers and means for pivotally mounting said first and second levers at opposite ends of the motor chamber so that the levers are pivotable by the reciprocable member as it nears the ends of its strokes whereby the valve means can be operated.   
     
     
       9. A reciprocable device as defined in claim 8 wherein said driving means includes a third pivotally mounted lever at the same end of the chamber as the first lever, said first and third levers engaging the reciprocable member on opposite sides of the axis thereof near the end of one of the strokes of the reciprocable member. 
     
     
       10. A reciprocable device as defined in claim 8 wherein said driving means includes an elongated shaft between the first lever and the bistable spring means and movable by the first lever to drive the bistable spring means over center in one direction. 
     
     
       11. A reciprocable device as defined in claim 8 wherein said bistable spring means includes a hinge member having first and second recesses therein, first and second arms having their inner ends receivable in the recesses and being movable with the hinge member over center between first and second states, spring means for urging the inner ends of the arms into the recesses, said driving means includes an elongated member drivingly engageable with said first lever and said hinge pin to move the hinge pin from one of the states thereof through the neutral position toward the other state thereof and a driving member drivable by the second lever and engageable with the hinge pin for driving the hinge pin from said other state over center toward said one state. 
     
     
       12. A reciprocable device as defined in claim 8 wherein said pivotal mounting means includes an abutment and a cooperating surface on the first lever engageable with the abutment and adapted to roll on the abutment to pivot said first lever. 
     
     
       13. A reciprocable device as defined in claim 12 wherein said pivotal mounting means includes a pin coupled to said first lever which is sufficiently resilient to accommodate the rolling movement of said first lever on the abutment.